When you want to convey that you are on top of everything, it means that you are in control and aware of everything that is happening. There are plenty of synonyms that can be used to express this idea, such as "in control," "on the ball," "up to date," or "on the pulse." Other synonyms could include "in touch," "on the same page," "in the know," "ahead of the game," or "in charge." All of these expressions communicate a sense of being knowledgeable, alert, and fully engaged with one's surroundings. Ultimately, each of these synonyms can be used in a variety of contexts to convey the same message of being on top of everything.